/**
 * $RCSfile$
 * $Revision: $
 * $Date: $
 *
 * Copyright 2003-2007 Jive Software.
 *
 * All rights reserved. Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.jivesoftware.smack;

import org.jivesoftware.smack.filter.PacketIDFilter;
import org.jivesoftware.smack.packet.Authentication;
import org.jivesoftware.smack.packet.IQ;

import org.apache.harmony.javax.security.auth.callback.CallbackHandler;
import org.apache.harmony.javax.security.auth.callback.PasswordCallback;
import org.apache.harmony.javax.security.auth.callback.Callback;

/**
 * Implementation of JEP-0078: Non-SASL Authentication. Follow the following <a
 * href=http://www.jabber.org/jeps/jep-0078.html>link</a> to obtain more
 * information about the JEP.
 * 
 * @author Gaston Dombiak
 */
class NonSASLAuthentication implements UserAuthentication {

	private Connection connection;

	public NonSASLAuthentication(Connection connection) {
		super();
		this.connection = connection;
	}

	public String authenticate(String username, String resource,
			CallbackHandler cbh) throws XMPPException {
		// Use the callback handler to determine the password, and continue on.
		PasswordCallback pcb = new PasswordCallback("Password: ", false);
		try {
			cbh.handle(new Callback[] { pcb });
			return authenticate(username, String.valueOf(pcb.getPassword()),
					resource);
		} catch (Exception e) {
			throw new XMPPException("Unable to determine password.", e);
		}
	}

	public String authenticate(String username, String password, String resource)
			throws XMPPException {
		// If we send an authentication packet in "get" mode with just the
		// username,
		// the server will return the list of authentication protocols it
		// supports.
		Authentication discoveryAuth = new Authentication();
		discoveryAuth.setType(IQ.Type.GET);
		discoveryAuth.setUsername(username);

		PacketCollector collector = connection
				.createPacketCollector(new PacketIDFilter(discoveryAuth
						.getPacketID()));
		// Send the packet
		connection.sendPacket(discoveryAuth);
		// Wait up to a certain number of seconds for a response from the
		// server.
		IQ response = (IQ) collector.nextResult(SmackConfiguration
				.getPacketReplyTimeout());
		if (response == null) {
			throw new XMPPException("No response from the server.");
		}
		// If the server replied with an error, throw an exception.
		else if (response.getType() == IQ.Type.ERROR) {
			throw new XMPPException(response.getError());
		}
		// Otherwise, no error so continue processing.
		Authentication authTypes = (Authentication) response;
		collector.cancel();

		// Now, create the authentication packet we'll send to the server.
		Authentication auth = new Authentication();
		auth.setUsername(username);

		// Figure out if we should use digest or plain text authentication.
		if (authTypes.getDigest() != null) {
			auth.setDigest(connection.getConnectionID(), password);
		} else if (authTypes.getPassword() != null) {
			auth.setPassword(password);
		} else {
			throw new XMPPException(
					"Server does not support compatible authentication mechanism.");
		}

		auth.setResource(resource);

		collector = connection.createPacketCollector(new PacketIDFilter(auth
				.getPacketID()));
		// Send the packet.
		connection.sendPacket(auth);
		// Wait up to a certain number of seconds for a response from the
		// server.
		response = (IQ) collector.nextResult(SmackConfiguration
				.getPacketReplyTimeout());
		if (response == null) {
			throw new XMPPException("Authentication failed.");
		} else if (response.getType() == IQ.Type.ERROR) {
			throw new XMPPException(response.getError());
		}
		// We're done with the collector, so explicitly cancel it.
		collector.cancel();

		return response.getTo();
	}

	public String authenticateAnonymously() throws XMPPException {
		// Create the authentication packet we'll send to the server.
		Authentication auth = new Authentication();

		PacketCollector collector = connection
				.createPacketCollector(new PacketIDFilter(auth.getPacketID()));
		// Send the packet.
		connection.sendPacket(auth);
		// Wait up to a certain number of seconds for a response from the
		// server.
		IQ response = (IQ) collector.nextResult(SmackConfiguration
				.getPacketReplyTimeout());
		if (response == null) {
			throw new XMPPException("Anonymous login failed.");
		} else if (response.getType() == IQ.Type.ERROR) {
			throw new XMPPException(response.getError());
		}
		// We're done with the collector, so explicitly cancel it.
		collector.cancel();

		if (response.getTo() != null) {
			return response.getTo();
		} else {
			return connection.getServiceName() + "/"
					+ ((Authentication) response).getResource();
		}
	}
}
